Another racking method - Quad Eight pre's

[sverige_cruz]

Hello all! First off, sorry for bumping the cooler threads down, but you gotta post sometime, right... :guinness: :guinness: That said, I'd like to offer yet another way to box up projects: the $2 space heater method, stright from the thrift store. It's just about the right size to rackmount - gotta get some ears though.

I also have a somewhat usable front panel layout for people with Quad Eight CA127/227 cards. (NOTE: you'll probably have to redraw some traces for your card, as I drew it up strictly for mine, and not all the pins match an original CA127/227). It ain't perfect, but it's a start. Use it for what you want. I don't have any education of PCB layout, so this might be the worst possible design, but it works, and nothing's burned up. Also, I haven't picked up any radio stations yet, so I'm sticking with it. I used edge connectors with solder tails (not pcb pins), cut a slot in the PCB for them and attached the edge connector to the pcb with small machine screws. Anyone interested in what the different traces are, if you want to use this, PM me and I'll try to put some info together.

I thought it might be easier to make these front boards and have them hooked up permanently, and slide the cards in, instead of a rat's nest of wires. If you want to see the rat's nest, check my limited traffic geocities website.

Also, the labelling was done with Avery iron-on paper and an ink-jet printer, and sprayed with a clear coat. There are more pics with the following links:

http://img.villagephotos.com/p/2006-3/1166256/6.9cm_wide_x_7.15.jpg
http://img.villagephotos.com/p/2006-3/1166256/top_inside.jpg
http://img.villagephotos.com/p/2006-3/1166256/9.22cm_wide_x_6.89.jpg
http://img.villagephotos.com/p/2006-3/1166256/front_angle.jpg
http://img.villagephotos.com/p/2006-3/1166256/front_wide.jpg
http://img.villagephotos.com/p/2006-3/1166256/qe_box_inside_top.jpg

Oh yeah. Cheers to everyone here! :guinness: You people are great!
Best Regards,
Jesus

 

[jameshspencer3]

love the "slightly" used look. very nice

 

[al_p]

i like the hot/cold faucet[gain]

looks cool!

 

[al_p]

i like the hot/cold faucet[gain]

looks cool!

 

[Orphan Audio]

Fun!
Your PCB design looks a lot like the prototype preamp kits we built over a year ago.

You will find the "Ouncer" input transformers pinch the performance of the cards somewhat because of limited bandwidth and level handling. I have replaced dozens of them in ADM modules and the improvement is spectacular.

I noticed the 127 cards you used are homebrew. What output transformer did you use? They look european with that dark laquer, and are much smaller than the factory trannies.
The character of the original Qee-3442 steel output transformer is the true magic of the 227 preamp. The 5 transistor opamp used in the 127 can be easily tweaked for better stability, lower distortion and bandwidth, comparable to the performance of the 127a,s and 137,s.

Check out the Quad Eight CA-227 preamp kit at www.orphanaudio.com
It uses the full capabilities of the cards, works on CA-127, 127a, and 137 cards, and is supplied with a factory spec transformer from the original manufacturer. The kit provides a front panel switch for multiple input impedances. I am always surprised by the raves I get from guys who try our demo racks here in LA.
The best deal is Kit 2, which includes a tested original CA card for only $100 more. I see guys trying to get as much as $350 for them on ebay, untested and no docs! (insulting!)

Wow!.... that was blatantly commercial! (sorry)

Excellent work, enjoy.


Ken Hirsch / Orphan Audio, Quad Eight Electronics LLC
www.orphanaudio.com
www.quadeightelectronics.com

"Knowledge is free,... It's what you do with it that gets expensive."

 

[wilebee]

hi Ken

Wil

Wilebee

 

[Orphan Audio]

Oh,.... Hi there wil. Hows your QE toys?

Wait,.... am I being watched?


Ken Hirsch / Orphan Audio, Quad Eight Electronics LLC
www.orphanaudio.com
www.quadeightelectronics.com

"Knowledge is free,... It's what you do with it that gets expensive."

 

[sverige_cruz]

Thanks for the comments, Ken - much appreciated. This box will hold me over until I gather enough dough for the par-metal/front panel express method. I figure I can just drop it in, when I do that...

The first time I wired some of these boards up, I did it with wires (no front pcb) and I don't know what took me so long to think about it, but I saw your kits one day (I had seen them long before) and decided to try something like that. Works so far. I'm adding on Peter Purpose's extra board for pad & polarity.

What output transformer did you use? They look european with that dark laquer, and are much smaller than the factory trannies.

Using Quad Eight 3041's wired 1:2. I think I bought one from you. Yes, I did...pretty sure at least.

I haven't noticed any limitations from the O-10's yet. But I have one more card to throw in there - and that one is going to be using a Cinemag from an earlier group buy, so I can check it then. Still ain't a real CA227, but close, and sounds good to me. Whenever I get that last channel done, I'll post my experience. Thanks again.

-- Jesus

 

[wilebee]

Your not being watched Ken I have some q8 jpgs I can send to ad to your collection on your site. Are you getting some sleep now ? I know how you feel Squared (8 month old twins). for those of you how hasn't met Ken hirsh, a very nice fellow with a lot of good knowldge on quad eight, langevin and etc. welcom to the Lab Wil

Wilebee

 

[Orphan Audio]

Thanks Wil. I am getting a little more sleep, but you are a god with twins! (and still somewhat coherent after all that!?)
I would love the pix, send them when you can.


On the CA-227 output you used, I have never uncased a 3041 so that explains that. The 3441/2 output have wonderfully rich harmonics when driven hard due to the steel core. The 3041 will not handle the same level as the 3441/2 but it distorts at a much higher level. So you lose some character and tone in place of better thd.

You will hear a marked difference with the QE input tranny. If you use a 3440 be sure to use the 360k termination resistor on the secondary or all hell will break loose.


Ken Hirsch / Orphan Audio, Quad Eight Electronics LLC
www.orphanaudio.com
www.quadeightelectronics.com

"Knowledge is free,... It's what you do with it that gets expensive."

 

[gang of elk]

[quote author="Orphan Audio"]If you use a 3440 be sure to use the 360k termination resistor on the secondary or all hell will break loose.
[/quote]

hi ken, very interesting. i take it this doesn't apply to the cinemag 3440a..(??) i have some on the front of some ca127a's (w no termination of input secondary) and they're very well behaved.

 

[Orphan Audio]

All 3440,s built then or now were made by Cinemag/Reichenbach, and all require the termination or you will get high distortion, drastically altered frequency response and undesireable coupling effects to/from the source device as well as level issues. The 3440a is the same as the 3440 but with one more input tap.
Put an Audio Precision on your output and you will see amazing ugliness without the secondary term.

Ken

 

[gang of elk]

thanks for the heads up. very interesting indeed. i don't have any such instrument to check it myself but will put it on a pal's bench when i get a chance. curious to check it out. i've not yet added output attenuators so they barely get driven at all at this point. will sort them per your recommendation and wind 'em up a bit. :guinness:

 

[JustinS]

Hey Jesus,

(Or anyone else out there!) Do you have a wiring guide for the 3041 transformers laying around, I've got some to try out at the moment...

Justin.

 

[Orphan Audio]

For the 3041 wiring, go to this thread in the Orphan Audio forums:

http://www.orphanaudio.com/index.php?topic=46

Gain thru the 3041 will be different depending on the impedance selected.

A pinout and wiring diagram library is planned on the Orphan Audio website and any new products from Quad EightElectronics will be documented there.